The tetrapyrrole compounds such as porphyrin and chlorophyll are compounds important and useful as a variety of medical and pharmaceutical agents such as anticancer agents and, in addition thereto, they have also been used as food additives, and oxidation-reduction catalysts in the fields of electronics. Such a tetrapyrrole compound is in general prepared according to a chemical synthesis method. However, this chemical synthesis method suffers from such a problem that it requires the use of specific equipment (manufacturing equipment) and a specific catalyst and some of the chemical synthesis methods may adversely affect the environment due to the solvent used therein.
Over against this, there has been proposed a method for the preparation of a tetrapyrrole compound which makes use of a microorganism. For instance, there has been known a method in which a variant of the microorganism belonging to the genus Plectonema which is a kind of photosynthetic bacteria is cultivated and the resulting protochlorophyllide is then isolated and recovered from the culture medium (see, for instance, Patent Document 1 specified below). Moreover, there has been known a method in which photosynthetic bacteria are cultivated to thus isolate and recover the resulting tetrapyrrole compounds (see, for instance, Patent Documents 2 and 3 specified below). In addition, there has also been known a method in which a microorganism belonging to the genus Arthrobacter is cultivated in a culture medium containing a specific compound and then the resulting uroporphyrin is then collected from the culture medium (see, for instance, Patent Document 4 specified below).
Patent Document 1: Japanese Un-Examined Patent Publication Hei 5-91866;
Patent Document 2: Japanese Un-Examined Patent Publication Hei 5-244937;
Patent Document 3: Japanese Un-Examined Patent Publication 2000-23691;
Patent Document 4: Japanese Un-Examined Patent Publication Hei 5-38295.